Protection sleeve for dip tubes

ABSTRACT

To prevent plugging of dip tubes used for bubbling gases into molten material a sleeve having a plurality of openings therein is attached to the end of the dip tube.

[ll] 3,6W 24 State s ate i References Cited [72] Inventor Clarence D. Hill T TTT mwwuuu B WWW 6 666 6 222 2 S mm mm N n m m m m m" -U T m m H Wi A n" a 01mm S "u .L E U" mam T nym mm A "m k w mk "mm .me.muo wFBFBBM u/089920 65 67 999999 HHHHH 2689 2 I ll 524880 97026 .423 292535 93 64 2 32 33 V. n a P m o C M 0 fiX H N 9k, a 11R. H 4 kW wm umm AzMnAN 0 de mm 1- m Wemw S Ha AFPA nflfl 2247 [54] PROTECTION SLEEVE FOR DIP TUBES Primary Examiner-Gerald A. Dost Attorney-Robert R Cochran 11 Claims, 7 Drawing Figs.

ABSTRACT: To prevent plugging of dip tubes used for bubbling gases into molten material a sleeve having a plurality of openings therein is attached to the end. of the dip tube [51] lnt.CIl.................. [50] Field of 34 T, 34 L, 34 PT; 75/59, 60, 49

PROTECTION SILIEIEVIE IFOR Dill? TUBES BACKGROUND OF THE INVENTION This invention relates to reactions involving the introduction of gases into liquids which are susceptible to freezing if they are exposed to temperatures very much below the reaction temperature. In particular, this invention relates to reactions wherein gases are bubbled into molten salts, hydroxides, and the like.

The prior art teaches that gases generally are introduced into molten material by immersing the outlet end of a dip tube into the molten material and introducing the gas under pressure through the dip tube. Many such reactions are carried out at temperatures just above the melting point of the molten material and it is under these conditions that there is often a problem with maintaining the dip tube so that it will allow gases to pass therethrough. When adjusting the gas flow rate and during shutdowns there can be a reduction in the gas flow which will cause a momentary suction on the gas line drawing some of the molten material into the dip tube. When this suction is of a magnitude that it causes the liquid drawn into the tube to attain a level above that of the material in the reaction vessel it tends to freeze; plugging the clip tube.

SUMMARY OF THE INVENTION Accordingly it is an object of this invention to prevent the plugging of dip tubes used for introducing gases into molten material.

It is a further object to prevent molten material from being drawn into the clip tube to levels above that of the material in the reactor.

It is a further object to prevent the plugging without the use of any movable parts at the outlet ofthe dip tube.

1 have found that by attaching a sleeve, having an inside diameter corresponding to the outside diameter of the dip tube, and having a plurality of openings therein, over the outlet end of the dip tube, prevents the liquid material from being drawn into the dip tube above the level of the liquid during periods of gas interruption and reactor shutdown thereby maintaining the molten material at temperatures wherein it will remain in a liquid state. This eliminates the blocking ofthe dip tubes which have hampered extended operations of prior art apparatus.

A better understanding of the invention can be obtained by further discussion in conjunction with the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a preferred embodiment of the sleeve attached to a dip tube and operationally immersed in a liquid.

FIG. 2 is an enlarged cross-sectional view of the dip tube and attached sleeve through line 22 of FIG. 1.

FIG. 3 is a cross-sectional view of the sleeve through line 33 of FIG. 2.

FIGS. 4, 5, 6, and 7 are views of other sleeves which are within the scope ofthe invention.

DETAILED DESCRIPTION OF THE DRAWINGS In FIG. ll can be seen the outline of a reactor 10 with a dip tube 112 having a sleeve M attached thereto immersed in a molten liquid. The bore diameter 16 of the sleeve 14 generally corresponds with the outside diameter of the dip tube 12 and the sleeve contains a plurality ofopenings, i.e., 20 and 22. The sleeve can be pressed onto the dip tube or it can be welded to the dip tube or secured to the dip tube in any other suitable manner which would withstand the conditions under which the reaction will take place.

The openings 20 and 22 in the sleeve 14 can be seen to better advantage in FIG. 2. While the exact dimensions of the openings can be varied, it is necessary that the openings allow for flow of the liquid freely through them.

FIG. 3 shows the cutaway view of the opening 22 in the sleeve 14 and indicates that in general the openings need not extend more than halfway through the cross-sectional area of the sleeve.

While the exact nature of the principles involved is not understood, I have found that placement of the sleeve over the dip tube prevents the molten material from being drawn up into the dip tube during periods of interrupted gas flow and during shutdown and it is believed that the plurality of openings in the sidewall of the sleeve creates counter currents and turbulence at the various openings. These currents tend to react against one another, quite opposed to the smooth flow which occurs when the dip tube is used without the sleeve of my invention.

As stated earlier, the size and shape of the plurality of opening can be varied and in FIGS. il, 5, 6, and 7 respectively, sleeves d0, 50, 60 and respectively show various opening such as 4l2, 52, 62 and 72 which are within the scope of the invention. These are merely for purposes of example and it is realized that those skilled in the art can use openings of other shapes and relative sizes which are considered to be within the scope of the disclosure.

EXAMPLE I A clip tube of %-II'ICI1 inside diameter aluminum tubing was fitted with a 3/ l 6-inch inside diameter aluminum sleeve which was 2-inches long. The sleeve had slots cut across the tubing at 1 inch and l% inches from the end of the sleeve attached to the dip tube and the dip tube was positioned just above the top slot within the sleeve. The dip tube and sleeve were placed into a reactor containing molten NaOH and alumina. Oxygen and propane were introduced into the reactor through the dip tube containing the molten hydroxide at varying feed rates for a period of 8 hours at which time the reaction was stopped and the sleeve removed from the dip tube. Examination of the dip tube indicated no buildup of any solids therein.

EXAMPLE II Under conditions identical to those of example I, except that a dip tube was used without a protective sleeve, it was found that the run could not be continued for any extended periods of operation as the dip tuzbe tended to become blocked. On a typical run without the protective sleeve, blockage of the dip tube occurred at 30 minutes.

I claim:

I. In combination with a dip tube used for bubbling gases into a liquid material a sleeve, having an inside diameter larger than the inside diameter of said dip tube connected at one end to the outlet end of said dip tube and open at the opposite end and having a plurality of openings on its axial length whereby said sleeve prevents the liquid material from being drawn into the dip tube by the partial vacuum created when shutdowns or momentary interruptions occur in the gas flow through the dip tube.

2. The sleeve of claim I wherein the inside diameter corresponds to the outside diameter of the dip tube.

3. The sleeve of claim 2 which is attached to the clip tube by pressing it over the dip tube.

41. The sleeve of claim I wherein the openings are slots cut perpendicular to the axis of the sleeve.

5. The sleeve of claim ll wherein the openings are cut paral lel to the axis of the sleeve.

6. The sleeve of claim ll wherein the openings are slots cut at an acute angle with respect to the axis of the sleeve.

7. The sleeve of claim 1 wherein the openings are circular.

h. The sleeve of claim 1 wherein the openings are triangular.

9. In a dip tube for use in bubbling gases into molten material the improvement which comprises attaching a sleeve open at both ends having a plurality of openings therein over the outlet end of said dip tube, wherein said sleeve prevents the molten material from being drawn into the dip tube during periods when the gas flow through the: tube is temporarily interrupted or during shutdown of the apparatus.

110. The sleeve of claim 9 wherein the inside diameter corresponds to the outside diameter of the dip tube.

l l. The sleeve of claim 9 wherein the openings are slots cut perpendicular to the axis of the sleeve.

I I? k l 

1. In combination with a dip tube used for bubbling gases into a liquid material a sleeve, having an inside diameter larger than the inside diameter of said dip tube connected at one end to the outlet end of said dip tube and open at the opposite end and having a plurality of openings on its axial length whereby said sleeve prevents the liquid material from being drawn into the dip tube by the partial vacuum created when shutdowns or momentary interruptions occur in the gas flow through the dip tube.
 2. The sleeve of claim 1 wherein the inside diameter corresponds to the outside diameter of the dip tube.
 3. The sleeve of claim 2 which is attached to the dip tube by pressing it over the dip tube.
 4. The sleeve of claim 1 wherein the openings are slots cut perpendicular to the axis of the sleeve.
 5. The sleeve of claim 1 wherein the openings are cut parallel to the axis of the sleeve.
 6. The sleeve of claim 1 wherein the openings are slots cut at an acute angle with respect to the axis of the sleeve.
 7. The sleeve of claim 1 wherein the openings are circular.
 8. The sleeve of claim 1 wherein the openings are triangular.
 9. In a dip tube for use in bubbling gases into molten maTerial the improvement which comprises attaching a sleeve open at both ends having a plurality of openings therein over the outlet end of said dip tube, wherein said sleeve prevents the molten material from being drawn into the dip tube during periods when the gas flow through the tube is temporarily interrupted or during shutdown of the apparatus.
 10. The sleeve of claim 9 wherein the inside diameter corresponds to the outside diameter of the dip tube.
 11. The sleeve of claim 9 wherein the openings are slots cut perpendicular to the axis of the sleeve. 